The flow field off southwest India at 8N during the southwest monsoon of August 1993

被引:37
作者
Stramma, L
Fischer, J
Schott, F
机构
[1] Institut für Meereskunde, Universität Kiel, 24105 Kiel
关键词
D O I
10.1357/0022240963213448
中图分类号
P7 [海洋学];
学科分类号
0707 ;
摘要
The flow field off the southwest coast of India at 8N was investigated during RV Sonne cruise 89 in August 1993 by direct velocity observations from shipboard- and lowered-ADCP and geostrophic computations from CTD stations. The upper ocean between 75E and 76 degrees 52'E near the South Indian shelf was governed by a northward flow with a subsurface velocity maximum of 25 cm s(-1) at about 100 m depth. This flow, organized as a poleward undercurrent hugging the continental slope, is typical for the southwest monsoon season. The northward transport in August 1993 was 4.7 Sv (1 Sverdrup = 10(6) m(3) s(-1)) for the upper 300 m from the shipboard ADCP. Earlier geostrophic observations showed southward surface flow above the poleward undercurrent, but in August 1993 the northward flow reached to the surface and in the geostrophy calculations, i.e. without the southward Ekman flow near the surface, there was even no clear subsurface core. The T-S characteristics show that Bay of Bengal Water (BBW) was carried with this flow, and low wind conditions seemed to be connected to the flow of BBW from the southern tip of Sri Lanka toward the southwest coast of India. Further offshore, two meridional current bands were identified in the upper 300 m of the ocean. West of the coastal undercurrent a band of southward flow existed with velocities up to 35 cm s(-1) above and to the east of the Chagos-Laccadive Ridge, from 72 degrees 10'E to 75E. The associated geostrophic transport in the upper 500 m was 5.2 Sv. As the T-S relation was different from that of the northward flow, this current band was not a local recirculation of the poleward undercurrent. Further west, the flow was weak, but intensified toward the central Arabian Sea, between 66E and 69 degrees 20'E, where another southward current band was found with velocities of up to 20 cm s(-1) and a total geostrophic transport for the upper 300 m of -7.2 Sv.
引用
收藏
页码:55 / 72
页数:18
相关论文
共 28 条
[11]   3-DIMENSIONAL SHELF CIRCULATION ALONG AN EASTERN OCEAN BOUNDARY [J].
MCCREARY, JP ;
CHAO, SY .
JOURNAL OF MARINE RESEARCH, 1985, 43 (01) :13-36
[12]   SURFACE CURRENT DISTRIBUTIONS IN THE TROPICAL INDIAN-OCEAN DERIVED FROM COMPILATIONS OF SURFACE BUOY TRAJECTORIES [J].
MOLINARI, RL ;
OLSON, D ;
REVERDIN, G .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 1990, 95 (C5) :7217-7238
[13]   SEASONAL-CHANGES IN THE DENITRIFICATION REGIME OF THE ARABIAN SEA [J].
NAQVI, SWA ;
NORONHA, RJ ;
SOMASUNDAR, K ;
SENGUPTA, R .
DEEP-SEA RESEARCH PART A-OCEANOGRAPHIC RESEARCH PAPERS, 1990, 37 (04) :593-611
[14]   MAINTENANCE OF THE LOW-OXYGEN LAYER IN THE CENTRAL ARABIAN SEA [J].
OLSON, DB ;
HITCHCOCK, GL ;
FINE, RA ;
WARREN, BA .
DEEP-SEA RESEARCH PART II-TOPICAL STUDIES IN OCEANOGRAPHY, 1993, 40 (03) :673-685
[15]  
QUADFASEL DR, 1982, J PHYS OCEANOGR, V12, P1358, DOI 10.1175/1520-0485(1982)012<1358:WMDAIL>2.0.CO
[16]  
2
[17]   EVOLUTION OF THE CLIMATOLOGICAL NEAR-SURFACE THERMAL STRUCTURE OF THE TROPICAL INDIAN-OCEAN .1. DESCRIPTION OF MEAN MONTHLY MIXED LAYER DEPTH, AND SEA-SURFACE TEMPERATURE, SURFACE CURRENT, AND SURFACE METEOROLOGICAL FIELDS [J].
RAO, RR ;
MOLINARI, RL ;
FESTA, JF .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 1989, 94 (C8) :10801-10815
[18]   CURRENTS AND TRANSPORTS OF THE MONSOON CURRENT SOUTH OF SRI-LANKA [J].
SCHOTT, F ;
REPPIN, J ;
FISCHER, J ;
QUADFASEL, D .
JOURNAL OF GEOPHYSICAL RESEARCH-OCEANS, 1994, 99 (C12) :25127-25141
[19]   THE COASTAL CURRENT OFF WESTERN INDIA DURING THE NORTHEAST MONSOON [J].
SHETYE, SR ;
GOUVEIA, AD ;
SHENOI, SSC ;
MICHAEL, GS ;
SUNDAR, D ;
ALMEIDA, AM ;
SANTANAM, K .
DEEP-SEA RESEARCH PART A-OCEANOGRAPHIC RESEARCH PAPERS, 1991, 38 (12) :1517-1529
[20]   HYDROGRAPHY AND CIRCULATION OFF THE WEST-COAST OF INDIA DURING THE SOUTHWEST MONSOON 1987 [J].
SHETYE, SR ;
GOUVEIA, AD ;
SHENOI, SSC ;
SUNDAR, D ;
MICHAEL, GS ;
ALMEIDA, AM ;
SANTANAM, K .
JOURNAL OF MARINE RESEARCH, 1990, 48 (02) :359-378